lm7341mfx National Semiconductor Corporation, lm7341mfx Datasheet - Page 16

• Manufacturer Part Number: lm7341mfx
• Description: Lm7341 Rail-to-rail Input/output ?15v, 4.6 Mhz Gbw, Operational Amplifier In Sot-23 Package
• Manufacturer: National Semiconductor Corporation

www.national.com
INVERTING COMPARATOR WITH HYSTERESIS
The inverting comparator with hysteresis requires a three re-
sistor network that is referenced to the supply voltage V
the comparator, as shown in Figure 3. When V
verting input is less than V
node of the comparator (V
(for simplicity assume V
three network resistors can be represented as R
with R
When V
low, very close to ground. In this case the three network re-
2
. The lower input trip voltage V
IN
is greater than V
V
A1
= V
CC
OUT
R
IN
A
A
2
, the voltage at the non-inverting
< V
(V
/ ((R
switches as high as V
IN
A
), the output voltage is high
1
> V
||R
A
3
A1
) + R
), the output voltage is
FIGURE 3. Inverting Comparator with Hysteresis
is defined as
2
)
1
||R
IN
3
at the in-
CC
in series
). The
CC
of
16
sistors can be presented as R
upper trip voltage V
The total hysteresis provided by the network is defined as
For example to achieve 50 mV of hysteresis when V
set R
resistors selected the error due to input bias current is ap-
proximately 1 mV. To minimize this error it is best to use low
resistor values on the inputs.
1
= 4.02 kΩ, R
V
A2
= V
2
A2
= 4.02 kΩ, and R
Delta V
CC
is defined as
(R
2
||R
A
= V
3
20206056
) / ((R
2
||R
A1
- V
3
1
3
in series with R
+ (R
A2
= 1.21 MΩ. With these
2
||R
3
)
CC
1
= 30V
. The